So in the video my instructor sent on viruses, he said that for lytic viruses, new viruses manufactured by the host cell could get out of the cell in one of two ways.

The new viruses would leave by exocytosis.
or,

The cell would be "ruptured" and the new viruses would "erupt out of the cell".

In the rupturing option, is the cell destroyed? The way he phrased it as well as his tone of voice brought to mind an image of the cell bursting and the viruses spilling out....but the diagram showed a little gap in the cell membrane, and the viruses leaving from that one exit point.

1 Answer
1

Yes, ruptured here means that the host cell is destroyed. The virus "hijacks" the cell anyway and uses its protein production machinery to make as much virus particles and its transcription enzymes to makes as many viral genomes as possible. If the ressources of the cell are exhausted, it get destroyed and the viruses are set free.

See this image (from the Wikipedia article on the lytic process). It actually doesn't matter, if the virus infects the cell from the outside or if it comes from the genome.

I understand now that the cell is destroyed either way. But is it more likely to be destroyed physically (ruptured) or because of exhaustion of resources?
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evamvidMar 10 '14 at 17:34

1

Rupture and release of the virus happens, when the ressources are exhausted. So one event happens before the next. Then there are phages, which can leave the cell without destroying them before, the phage M13 is such an example. It expresses proteins which make a pore in the cells membrane which the phages can pass.
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ChrisMar 10 '14 at 17:38

After the phages leave, what happens to the cell? Does it still have the viral DNA? Does it make more viruses? Or does it carry on with normal business like it was never infected?
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evamvidMar 10 '14 at 17:45

Its dead. The membrane is destroyed, and it can not do anything anymore.
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ChrisMar 10 '14 at 18:29

I'm confused...I thought you said that some phages can exit without destroying the cell by expressing proteins which basically open a hole in the cell membrane and let the phages out. Is that correct? If so, what I was trying to figure out is, after this process, does the undestroyed cell then carry on with normal business, or does it keep making viruses?
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evamvidMar 10 '14 at 18:32